The present invention relates to a throttle valve configuration having an emergency air device for the intake system of an internal combustion engine.
Such an emergency air device has the purpose, when the drive of the throttle valve drive fails, of moving the throttle valve into an emergency air position in which the internal combustion engine is supplied with sufficient air to travel to a garage or to another location (limp home). In the prior art (see for example U.S. Pat. No. 5,975,051) such an emergency air device is formed, for example, from two external springs which act in opposite directions and associated stops which ensure that, when the drive fails, the throttle valve is moved into a position (emergency air position) which lies between the idling position and the open position. The disadvantage here is that the drive of the throttle valve must operate counter to the force of this additional spring system. For this reason, the drive must be configured larger than necessary in order to achieve a sufficient adjustment speed. It is even more critical that the emergency operating position results in a discontinuity in the adjustment path and in the adjustment movement of the throttle valve, which requires a non-linear pilot control with corresponding control expenditure.
It is accordingly an object of the invention to provide a throttle valve configuration which overcomes the above-mentioned disadvantages of the prior art apparatus of this general type.
In particular, it is an object of the invention to provide a throttle valve configuration having an emergency air device that requires only the smallest possible drive force and permits linear pilot control of the throttle valve.
With the foregoing and other objects in view there is provided, in accordance with the invention, a throttle valve configuration having an emergency air device for an intake system of an internal combustion engine having an intake duct with a wall. The throttle valve configuration includes: a throttle valve and an additional valve rotatable about a common axis in the intake duct of the internal combustion engine; a restoring spring for providing a force; an additional spring for providing a force between the throttle valve and the additional valve; a drive providing a force for commonly adjusting the throttle valve and the additional valve in an opening direction counter to the force of the restoring spring; and an emergency air opening penetrating the throttle valve. The additional valve is capable of rotating relative to the throttle valve about a predefined emergency air release angle such that when the drive fails, the restoring spring moves the additional valve, counter to the force of the additional spring, out of an emergency air shut-off position in which the additional valve closes off the emergency air opening and into an emergency air release position in which the additional valve releases the emergency air opening so that the internal combustion engine can be supplied with sufficient internal combustion air enabling emergency operation.
In accordance with an added feature of the invention, there is provided, a first drive connection connecting the drive to the additional valve; and a second drive connection connecting the restoring spring to the additional valve. The additional valve transmits the force of the drive and the force of the restoring spring to the throttle valve.
In accordance with an additional feature of the invention, the throttle valve, the additional valve and the additional spring are configured such that the force of the drive is transmitted to the throttle valve by a direct abutment between the additional valve and the throttle valve; and the additional spring transmits the force of the restoring spring to the throttle valve via the additional spring.
In accordance with another feature of the invention, the force of the restoring spring is greater than the force of the additional spring.
In accordance with a further feature of the invention, when the drive fails, the throttle valve is pressed against a fixed stop by the restoring spring via the additional valve and the additional spring, after which the restoring spring moves the additional valve into the emergency air release position counter to the force of the additional spring.
In accordance with a further added feature of the invention, concentric shafts rotatably mount the throttle valve and the additional valve in the wall of the intake duct.
In accordance with a further additional feature of the invention, the additional valve is embodied as a double-armed lever having a first lever arm and a second lever arm. The first lever arm is embodied as a valve part that closes off the emergency air opening. The second lever arm is inclined with respect to the valve part by an angle that corresponds to the emergency air release angle.
In accordance with yet an added feature of the invention, there is provided, a first sensor for sensing the angle of rotation of the throttle valve.
In accordance with yet an additional feature of the invention, there is provided, a second sensor for sensing the angle of rotation of the additional valve.
In accordance with yet another feature of the invention, there is provided, a device for sensing the emergency air release angle by forming a difference between the angle of rotation of the throttle valve and the angle of rotation of the additional valve.
In the throttle valve configuration, the throttle valve is provided with an emergency air opening that is normally closed by the additional valve. If the drive fails, the restoring spring moves the additional valve counter to the force of the additional spring that acts between the two valves, and into the emergency air release position in which the additional valve releases the emergency air opening. The emergency air opening is dimensioned in such a way that, despite the fact that the throttle valve is closed, the internal combustion engine is supplied with sufficient air to permit emergency operation of the vehicle.
Given the normal operation of the throttle valve configuration, the throttle valve and the additional valve are moved together by the drive and no force has to be overcome other than the force of the restoring spring that is present in any case. For this reason, the drive does not need to have larger dimensions than is necessary to operate a throttle valve without an emergency air device. In addition, there is no discontinuity in the adjustment path of the throttle valve configuration so that linear pilot control of the throttle valve configuration is made possible. The controller that is assigned to the throttle valve configuration therefore operates significantly less critically than in the prior art.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a throttle valve configuration having an emergency air device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.